Relationship between diabetic retinopathy and subclinical myocardial dysfunction in patients with diabetic mellitus

Abstract

BACKGROUND: Diabetic mellitus (DM) patients may have cardiac structure and functional changes or microvascular disease in the absence of cardiovascular disease history. The relationship between the occurrence of diabetic microvascular disease and cardiac change in DM patients without a history of heart trouble is unclear. The present study sought the correlation between diabetic retinopathy, which is one kind of microvascular disease, and cardiac functional changes by (a) basic ophthalmic testing and (b) detailed echocardiography for cardiac assessment. METHODS: A total of 251 patients with type 2 DM without cardiovascular diseases were recruited. Transthoracic echocardiography was performed at the rest state as well as after treadmill exercise and analysed in detail with the following parameters: (i) left ventricle (LV) systolic function was assessed by Simpson’s method derived ejection fraction (EF) and speckle tracking derived global longitudinal strain (GLS), (ii) myocardial structural alteration by calibrated integrated backscatter (cIBS), (iii) diastolic function by tissue Doppler derived E/E’ ratio, and (iv) diastolic function reserve index (DFRI). Furthermore, all patients undertook a full-fledged photography programme. Retinopathy was scored and classified as with retinopathy or without diabetic retinopathy. RESULTS: Of the 251 subjects (mean age, 63.13 ± 9.31 years; 46.2% male), 24.3% had retinopathy. Patients with and without diabetic retinopathy (as a categorical variable) had similar LVEF and cIBS. However, retinopathy had a significant correlation with LV GLS (r = –0.18, P < 0.01), E/E’ (r = 0.19, P < 0.01), diastolic dysfunction grade (r = 0.18, P < 0.01), and DFRI (r = –0.23, P = 0.02). Furthermore, these correlations were independent of potential confounding factors. CONCLUSION: This study indicated that the occurrence of retinopathy significantly correlates with GLS, E/E’, diastolic dysfunction grade, and DFRI. Above all, the correlation still existed after adjusted by potential confounding factors, suggestive of an independent relation between retinopathy and cardiac function. The link between these parameters highlighted the importance of further cardiac assessment and timely treatment for DM patients with diabetic retinopathy who have no cardiac disease history and relevant symptoms.